Cassette seals are already known from EP 0 814 288 A1. The advantage of cassette seals is that the running surface rests against the sealing lip, which is part of the seal, so that both these components can be perfectly matched to one another. Furthermore, the sealing lip rests already prior to installation in the correct position against the running surface of the internal ring so that damage to the sealing lip occurring during installation of the cassette seal on the rotating machine element can be excluded. The cassette seal is associated with a further advantage in that the internal ring covers the sealing body at least in part on the outside, thus protecting it from the ingress of excessive contamination. For this reason, cassette seals are often used in devices exposed to high loads. Examples include agricultural machinery, construction equipment or rail vehicles. All this machinery and equipment is subjected to very considerable fluctuations in temperature on the one hand, and to the ingress of undesirable media such as water on the other hand. The fact that the radially projecting part of the internal ring projects beyond the sealing lip enables the sealing lip to be encapsulated and therefore to be protected against influences entering from the outside.
However, the use of the cassette seal in low-temperature conditions is problematic. This particularly applies when the seal is subjected in parallel to the effect of water. In this context, the ingress of water into the gap between the internal ring and the external ring is undesirable.